Also it does seem to have been the subject of last-minute revisions: cabinet papers on additional detailed changes put on ice in the last 48 hours.

Image:The 'stay at home' slogan has been replaced with 'stay alert'

And Tory MPs who were furious with the headline change - to ditch the "stay at home" slogan and replace it with "stay alert" - were told the address was a "work in progress" even today.

Things changing, it seems, at the last minute. Parts were recorded yesterday, parts today.

The biggest message from the prime minister is that those who cannot work from home should go out to work.

Image:People will be allowed to do more exercise

Hearing this from Mr Johnson may have a big effect on manufacturing and construction.

Yet this is not even a change of policy - that has been the consistent position from the beginning, with ministers making it clear from the Commons at the start that builders should go to work.

That tells us that Number 10 views slogans like "stay at home" as more important than policy or law, meaning tonight's minimalist speech could have a more significant impact than they intend.

The combination change to allow more exercise a day and to sunbathing is more significant than it seems or that he spells out.

This is intended to signal that people who want to sit next to one friend on a park bench, albeit at a two-metre distance, will be able to. Why Mr Johnson couldn't spell this out more clearly isn't obvious.

Image:PM has suggested some schools could reopen in June

The rest of the speech is less plan, more a series of aspirations: perhaps primary schools reopening in June, perhaps public spaces in July.

But no specificity over what or under which circumstances, and all heavily caveated that this could be abandoned if the infection spreads more rapidly.

The schools point is significant though: that aspiration puts Mr Johnson once again at odds with the leaders of the devolved nations, especially in Wales which said on Thursday there was no chance Welsh schools would reopen then.

Small but significant differences over the lockdown legal framework is one thing; an English/Welsh difference over schools is quite another.

English teachers would then rightly be able to ask whether they are being put at more risk than their Welsh counterparts.

Mr Johnson's speech also avoids any answer to tough choices he needs to make:

Will employers be liable if people get coronavirus in the workplace? Will people who can't work for a year because of social distancing be supported by government to anything like current levels?

But he can't escape such difficult questions.

On Monday, Mr Johnson will face MPs including Labour leader Sir Keir Starmer in the Commons, the public that night and his own MPs on Tuesday night.